Lid with integrally molded pouring spout

ABSTRACT

A pail lid having a retractable pouring spout. The pail lid has a neck integrally formed as part of the lid and extending from the face of the lid opposed to a peripheral groove. The neck has external threads adapted to receive a screw cap. A retractable pouring spout located within the opening is movable from a pouring position to a retracted position while being retained within the neck. The spout mates with the neck at the pouring position and the retracted position. An injection molding process for manufacture of the lid is also disclosed.

The present invention relates to a lid for a pail in which there is apouring spout for the purpose of removing contents of the pail, and inparticular to a lid for a pail in which the pouring spout has beenintegrally injection molded with the remainder of the lid andsubsequently severed therefrom to provide a lid with a retractablespout. As used herein, pails include so-called plastic containers havinglids.

When the material within a pail is in a fluid form, including powdersand liquids, it is convenient to be able to pour the fluid from thecontainer without removing the lid from the container. It is easier andmore convenient to use a spout located on the lid to remove the contentsfrom the container, as opposed to removing the lid from the containerand pouring the contents directly from the lid-less container.

Lids having spouts are known and frequently used in the pail andcontainer business. Such lids have a neck in which a spout is attached,with the spout being movable from an inverted storage position andreattached in a pouring position prior to use. Alternatively, the lidmay have a spout that is movable, without being inverted, from a pouringposition to a storage position with the latter being adapted for sealingwith a cap.

The formation or manufacture of containers with lids with retractablespouts has required a multi-step manufacturing process, using at leasttwo separate molds. The lid is manufactured in one injection moldingoperation, normally with an orifice at the location where the spout isto be located. The spout is manufactured in a separate manufacturingprocess and subsequently attached to the lid by spin-welding orultrasonic welding, or by snap-fitting a spout into a hole in the lid.The latter is prone to leakage, especially due to non-uniform shrinkageof the lid after molding, which has led to attempts to mold non-circularholes that after shrinkage of the lid are circular in shape.

Such molding-techniques require the construction of separate molds forthe spout and for the remainder of the lid, as well as the carrying outof several steps in the process to form the lid with the retractablespout.

A lid with a retractable spout, and a method for the manufacturethereof, have now been found in which the lid and spout are formed inthe same molding operation.

Accordingly, the present invention provides a pail lid having aretractable pouring spout, said pail lid having opposed faces with anannular groove on one face at the periphery thereof for attachment to apail, said lid having an opening between said faces juxtaposed to saidannular groove with an annular neck surrounding said opening, said neckbeing integrally formed as part of said lid and extending from the faceof the lid opposed to said groove, said neck having external threadsthereon adapted to receive a screw cap, a retractable pouring spoutlocated within said opening that is movable from a pouring position to aretracted position while being retained within said neck, the spoutmating with the neck at each of the pouring position and the retractedposition.

The present invention also provides a method for the manufacture of apail lid having a retractable pouring spout, said pail lid havingopposed faces with an annular groove on one face at the peripherythereof for attachment to a pail, said lid having an opening betweensaid faces juxtaposed to said annular groove with an annular necksurrounding said opening, said neck being integrally formed as part ofsaid lid and extending from the face of the lid opposed to said groove,said neck having external threads thereon adapted to receive a screwcap, a retractable pouring spout located within said opening, said spoutbeing movable from a pouring position to a retracted position, whilebeing retained within said neck, the spout mating with the neck at eachof the pouring position and the retracted position, said methodcomprising:

(a) in injection molding apparatus, feeding molten thermoplastic polymerto a cavity of a mold for said lid, said cavity of the mold extendingbetween the neck and the spout with a narrow gate between said neck andspout,

(b) forming the lid with the neck integrally connected to the spout,cooling the polymer and ejecting the lid so formed from the injectionmolding apparatus,

(c) separating the spout from the neck by severing the polymer at thenarrow gate so that said spout is movable within said neck but beingretained therein.

In addition, the present invention provides in a method for themanufacture of a lid with a retractable pouring spout in which said lidis formed from a thermoplastic polymer, said pouring spout being locatedwithin a neck protruding from a face of said lid, said spout beingretained within the neck but being movable between a first position anda second position within said neck, the improvement comprising formingsaid lid in injection molding apparatus with said pouring spoutintegrally connected to said neck by a narrow gate of polymer, coolingthe lid so formed, separating the spout from the neck by severing saidpolymer at said narrow gate, such that the spout is movable between saidfirst and second positions.

In preferred embodiments of the method of the invention, the narrow gatebetween the neck and the spout extends around the circumference of theneck and spout.

In another embodiment, the molten polymer is fed to the cavity of themold for the lid through a gate centrally located therein.

The present invention will be described with particular reference to theembodiments shown in the drawings in which:

FIG. 1 is a schematic representation of a pail lid with a pouring spoutin the extended position;

FIG. 1A is a schematic representation of a pail with a pouring spout ina retracted position, with an end cap;

FIG. 2 is a schematic representation of a cross-section of the lid ofFIG. 1, during the manufacturing process;

FIG. 3 is a schematic representation of the pouring spout in the pouringposition, as seen from A--A of FIG. 1;

FIG. 4 is a schematic representation of the pouring spout in a retractedposition with an end cap, as seen from B--B of FIG. 1A;

FIG. 5 is a schematic representation of a cross-section of an alternateembodiment of a lid with pouring spout; and

FIG. 6 is a plan view of a pull-tab for the pouring spout.

FIG. 1 shows a lid, generally indicated by 1, that has an upper surfaceor face 2 and a spout 3. Spout 3 is located off-center on lid 1, andpasses through neck 4 which is integrally connected to upper surface 2.Lid 1 has edge 5 with ridge 6 extending above the plane of upper section2 and skirt 7 extending downwards from edge 5. Ridge 6 corresponds to agroove (not shown) on the underside of lid 1, which is used for locationand attachment of lid 1 on a pail. Spout 3 is shown in a pouringposition. It is understood that spout 3 would be juxtaposed to ridge 6but spaced therefrom, at a convenient location for pouring of thecontents of the pail from the pail; the location is referred to hereinas juxtaposed to the ridge/groove at the periphery of the lid.

The gate used in the injection molding of lid 1 is preferably located atthe center of upper surface 2.

FIG. 1A shows lid 1 of FIG. 1 with spout 3 in a retracted position.Spout 3 is not seen in FIG. 1A, as it is covered by end cap 9, such thata closure to the pail is formed. FIG. 1 represents the lid during usefor removal of the contents of the pail, whereas FIG. 1A represents thelid when on a container during storage or shipment. It is understoodthat lid 1 normally would be designed, in association with the design ofpails on which the lid would be used, such that end cap 9 would notinhibit the stacking of pails with lid 1, as will be understood bypersons skilled in the art. End cap 9 could be of a height less thanthat of ridge 6, but as pails are normally designed with a recessedunderside (bottom), end cap 9 could extend above ridge 6 for a distanceless that the depth of the recess on the underside of the pail on whichit is to be used.

In operation, lid 1 is placed on a pail e.g. a pail containing a fluid,for instance a powder or liquid. Spout 3 would normally be in aretracted position, with end cap 9 in position, so that the pail couldbe shipped or stored, including stacked in a warehouse. In such anarrangement lid 1 would seal the contents of the pail within the pail.At the time that fluid was to be poured from the pail, end cap 9 wouldbe removed from neck 4 and spout 3 would be extended into the positionshown in FIG. 1. The pail would then be tipped to a suitable degree sothat contents within the pail would flow from the pail.

In the method of the present invention, lid 1 is integrally molded in asingle molding step in a mold. Subsequent to the moulding step, aftercooling of the thermoplastic polymer, spout 3 is separated from theremainder of lid 1 so that it may be located in either a pouringposition or retracted position within neck 4. It is understood that itis intended that spout 3 would always be located within neck 4 i.e. itwill not fall out of neck 4 regardless of the orientation of the pail.

FIG. 2 shows a cross-section of lid 1 during the molding operation. Asshown, spout 3 is not in a fully extended position and is attached tothe remainder of lid 1. It is understood that the position of spout 3with respect to neck 4 may be varied, but it is convenient that spout 3be centrally located, to reduce the overall dimensions of the moldrequired.

In FIG. 2, lid 1 is shown as having upper surface 2, spout 3 and neck 4.Neck 4 has thread 10 located thereon, external to spout 3. The uppersection of spout 3 has arcuate protrusion 11, which is of the sameconfiguration as arcuate section 12 located on neck 4, such that thesurfaces will mate together. Similarly, the lower section of spout 3 haschamfered protrusion 13 which is of the same shape as chamfered section14 located on neck 4. Arcuate section 12 is located on the upperinterior position of neck 4 facing opening 16 in lid 1. Similarly,chamfered section 14 is located on the lower interior section of neck 4,facing opening 16. Neck 4 is connected to spout 3 at spout gate 15.Spout gate 15 is a narrow gate, and normally would be a circumferentialgate extending around spout 3, although other configurations may be usedprovided that acceptable melt flow is achieved during the moldingoperation.

In operation of the injection molding process, with reference to FIG. 2,molten thermoplastic polymer is injected through a gate into a moldcavity of the shape shown in FIG. 2. Molten polymer travels in thedirection indicated by the arrows 17. The part molded in the injectionmolding operation is as shown in FIG. 2. Techniques for such injectionmolding will be understood by persons skilled in the art.

Subsequent to the molding operation, after the thermoplastic polymer hasbeen cooled and the part has been removed from the mold, spout 3 isseparated from neck 4 by severing or breaking the polymer at gate 15.This permits spout 3 to move vertically within opening 16 of neck 4 froma position in which arcuate protrusion 11 mates with arcuate section 12to a position where chamfered protrusion 13 mates with chamfered section14.

FIG. 3 is a cross-section through A--A of FIG. 1. FIG. 3 shows spout 3in a pouring position, in which chamfered protrusion 13 is mated withchamfered section 14 to provide a seal between spout 3 and neck 4. Thisseal needs to be effective to the extent that fluid may be poured fromthe pail.

FIG. 4 is a cross-section through B--B of FIG. 1A. FIG. 4 shows spout 3in a retracted position such that arcuate protrusion 11 mates witharcuate section 12. Chamfered protrusion 13 of spout 3 extends downwardinto the pail. End cap 9 is located on neck 4, having been screwed ontothread 10. End cap 9 provides a seal for the pail, maintaining thecontents of the pail within the pail during storage. In the embodimentshown, end cap 9 and the mating of arcuate protrusion 11 with arcuatesection 12 provide the seal for the contents of the pail.

An alternate embodiment of a pail lid with a retractable pouring spoutis shown in FIG. 5, where the lid and pouring spout are generallyindicated by 20 and 21, respectively. Lid 20 has neck 22 with screwthread 23 thereon, for the purpose of attaching a screw cap. Neck 22 isspaced from annular groove 25 by gap 24; it is understood that neck 22would normally not be centrally located on lid 20 but would be disposedtowards the periphery thereof to facilitate removal of the contents ofthe pail through the spout. Lid 20 has an annular groove, generallyindicated by 25, that passes around the circumference of the lid, forthe purpose of attaching the lid to the container.

Annular lip 26 is located within neck 22, being spaced downwards fromupper edge 27 of neck 22. The periphery of lip 26, which forms theopening within spout 21 for passage of materials therethrough, isundercut (bevelled), as discussed below. A membrane, usually referred toas a tamper-evident liner, 28, is shown as being stretched across upperedge 27 of neck 22, for the dual purpose of sealing the contents in thepail and to provide evidence of any tampering with the contents of thepail. The tamper-evident liner may be formed from a variety ofmaterials, including a foil or a self-adhesive foam material, as will beunderstood by persons skilled in the art. Alternatively, tamper-evidentliner 28 may be part of cap 9 shown in FIG. 1A, especially forinstallation of liner 28.

Spout 30 is located within neck 22, in an abutting relationship with lip26, and extends downwardly within neck 22. Pouring spout 30 iscylindrical in shape throughout its length except that it is of slightlyincreased diameter at both of its ends, 31 and 32. The exterior surfaceof lower end 32 of pouring spout 30 has circumferential notch 34, forthe purpose of locating the bevelled end of lip 26 when pouring spout isin its extended position. Notch 34 is for retention of pouring spout 30in its extended position, as desired, during normal use of the pail.Pouring spout 30 may be moved from its extended position to itsretracted position by pushing the spout downwards with moderate pressuree.g. by forcing with the hand. Spout 30 may also be pulled upwards, butit is more convenient to do so in the manner discussed below.

Pull tab 40, more clearly seen in FIG. 6, is shown as being locatedwithin pouring spout 30, approximately at a location opposed to lip 26.Tab 40 is intended to assist in extension of pouring spout 30. While tab40 could be retained in spout 30 by friction i.e. be force-fit, it ispreferred that tab 40 be integrally molded into spout 30. Pull tab 40 isshown in FIG. 6 as having an annular ring 41, which is optional, withinpouring spout 30, and an internal tab 42. Tab 42 would normally havesome flexibility, and it is intended that a person be able to move spout30 from its retracted position to its extended position using tab 42e.g. with a hook or with one of more fingers.

The lid is molding from a thermoplastic polymer using an injectionmolding process. Thermoplastic polymers suitable for injection moldingare known. Such polymers include polyethylene, polypropylene and relatedpolymers. Polyethylene and polypropylene are preferred. However, the lidcould be formed from other thermoplastic polymers, including polyamides,polyesters and the like. As will be understood, the particularproperties of the thermoplastic polymer used for the manufacture of thelid will be selected so as to provide suitable flow properties in aninjection molding process while still retaining adequate properties forthe lid while in use.

Procedures for the injection molding of the lid will be understood bypersons skilled in the art. In particular, cycle times, pressures andtemperatures and other parameters required for suitable molding of theprocess will be understood. The gate to the cavity of the mold wouldnormally be located at the center of upper surface 2 of lid 1, althoughit could be located off-center. The narrow gate between spout 3 and neck4 would normally be a circumferential gate, with the mold having asuitable core located in the position of opening 16. Nonetheless, it isto be understood that gate 15 could be other than a circumferentialgate, provided that adequate flow from the neck to the spout wasachieved.

The present invention provides a method and a resultant lid, in whichthe lid is molded in a single molding operation in a single mold cavity,with the spout being separated from the remainder of the lid in asubsequent operation. Such a method offers improved economics in themanufacture of the lid, especially in that only one mold cavity isrequired and there are no subsequent fabrication steps in the processfor the manufacture of the lid, other than severing or breaking of thespout from the neck. Trimming may be required to provide a smoothsurface on the exterior surface of spout 3 so that the spout will moveeasily within the opening 16.

We claim:
 1. A pail lid having a retractable pouring spout, said paillid having opposed faces with an annular groove on one face at theperiphery thereof for attachment to a pail, said lid having an openingbetween said faces juxtaposed to said annular groove with an annularneck surrounding said opening, said neck being integrally formed as partof said lid and extending from the face of the lid opposed to saidgroove, said neck having external threads thereon adapted to receive ascrew cap, a retractable pouring spout located within said opening andretained within said neck by a breakable narrow spout gate that isintegrally formed with the retractable pouring spout and the neck, thespout gate being breakable by moving the spout with respect to the lidso as to provide a retractable pouring spout that is movable from apouring position to a retracted position while being retained withinsaid neck, the spout mating with the neck at each of the pouringposition and the retracted position using arcuate or chamfered sections.2. The paid lid of claim 1 in which the spout has at least one externalnotch intended to mate with a cooperative surface of a lip within theannular neck to retain the spout in its respective pouring and retractedpositions.
 3. The pail lid of claim 1 in which a tamper-evident membraneis placed across the upper surface of the neck.
 4. The pail lid of claim1 in which a pull tab is located within the pouring spout.
 5. The paillid of claim 1 in which the lid is formed from a thermoplastic polymer.6. The pail lid of claim 5 in which the polymer is polyethylene orpolypropylene.